I need a link to all of the unity libraries that are declared above class with the using keyword.
I need general outline of what each does.
You want a list of classes you can use? Well it uses .NET 2.0 which should have available:
But it might not be everything, for unity specific, then there is:
UnityEngine and UnityEditor
http://docs.unity3d.com/Documentation/ScriptReference/20_class_hierarchy.html and http://docs.unity3d.com/Documentation/ScriptReference/20_class_hierarchy.Editor_Classes.html respectively
Actually, it uses Mono 2.6.7 which includes a full implementation of the C# 3.0 language spec and a partial implementation of the C# 4.0 spec. It is more equivalent to .NET 3.5 than 2.0 as it also allows the use of LINQ queries. (LINQ was not available in .NET 2.0).
So when looking at the MSDN docs, you’re safe looking at .NET 3.5 specs and sort of okay-ish looking at .NET 4.0 specs.
I chose .NET 2.0 as a safe option as it contains all the commonly used stuff, but your right it has some .NET 3.5 stuff like Linq, as i use LINQ a lot.
And LINQ is a beast. I can’t speak for LINQ to SQL, but LINQ to Object is really handy. So very handy.